Auxiliary closing mechanisms for tenter clips



Feb. 11, 1964 c, NASH I 3,120,688

AUXILIARY CLOSING MECHANISMS FOR TENTER CLIPS Filed Dec. 21, 1961 2 Sheets-Sheet 1 Q l .36 a, .47 7 Fl 7 5 i /5 32 v INVENTOR.

m 5 JOHN CRANDON NASH A r TORNEV 1964 J. c. NASH 3,120,688

AUXILIARY CLOSING MECHANISMS FOR TENTER CLIPS Filed Dec. 21, 1961 2 Sheets-Sheet 2 IN VEN TOR.

JOHN CRA NDON NA 5/1 M A T TORNEY United States Patent 3,126,688 AUXILIARY CLQSING MECHANISMS FUR TENTER CLHS John Crantlon Nash, Providence, RI, asslgnor to Marshall and Williams Corporation, Providence, RI,

a corporation of Rhode Island Filed Dec. 21, 1%1, Ser. No. 161,177 2 (Jlaims. (Cl. 2662) This invention relates to improvements in tenter clips and more particularly to a construction which yieldingly urges the tenter clip jaw or gate into cloth gripping position.

An object of the present invention is to provide a tenter clip with an auxiliary force to yieldingly assist the forces of gravity which swing the jaw or gate into cloth gripping position.

Another object of the present invention is to produce a tenter clip with auxiliary means assisting the forces of gravity to cause the swing jaw or gate to engage the cloth or film with increasing initial force and to engage the cloth or film with increasing force the farther the swing jaw or gate is swung into clamping position.

Still another object of the present invention is to provide adjustable auxiliary means for assisting the forces of gravity to more quickly place a swing jaw or swing gate in cloth or film gripping position.

Other objects of the present invention will become apparent in part and be pointed out in part in the following specification and claims.

In the past a magnet was used as means to cause the swing jaw to engage the cloth with increasing force the harder the cloth pulled upon the gripping action of the swing jaw. United States Patent No. 1,119,824, dated December 8, 1914, discloses the magnet and a spring for this purpose. This patent discloses a swing jaw used with a controller.

The nature of the material processed in a tentering machine has greatly changed since 1914. T his necessitated a change in the structure and functional operation of the tenter clip swing jaw or gate. The present invention is directed to a structure adapted to accomplish proper gripping or holding of modern web materials.

In this specification cloth or film refers to any type of web material such as very thin slippery plastic film, thin hard finished textiles or webs of paper.

The modified forms of the present invention illustrated in FIGURES 6 through 10 are continuations-in-part of United States application Serial No. 823,886, filed June 30, 1959, for a Tenter Clip Gate, by John Crandon Nash, the present applicant, and now U.S. Patent No. 3,023,479.

This application is directed to the problem of tentcring and therefore gripping very thin slippery plastic film or very thin and very hard cloth.

The terms film, sheet or web are deemed synonymous in this specification.

Referring to the drawings in which similar characters of reference indicate corresponding parts in all the figures.

FIGURE 1 is a perspective View of a tenter clip embodying the new and improved adjustable auxiliary swing jaw closing mechanism.

FIGURE 2 is a perspective view of a tenter clip embodying a modified form of a new and improved adjustable auxiliary swing jaw closing mechanism.

FIGURE 3 is a plan view of FIGURE 2.

FIGURE 4 is a vertical cross sectional view taken on line 44 of FIGURE 3.

FIGURE 5 is a vertical cross sectional view taken on line 55 of FIGURE 1.

FIGURE 6 is a perspective view of a modified form of tenter clip embodying the new and improved adjustable 3,126,688 Fatented Feb. 11, l fi i auxiliary swing jaw closing mechanism illustrated in FIGURE 1.

FIGURE 7 is a side elevational view of FIGURE 6.

FIGURE 8 is a plan view of FIGURE 6.

FIGURE 9 is a vertical cross sectional view taken along line 99 of FIGURE 8.

FIGURE 10 is a vertical cross sectional view of the modified form of tenter clip shown in FIGURE 6 with the modified form of a new and improved adjustable auxiliary swing jaw closing mechanism.

FIGURES 1 and 5 illustrate a tenter clip generally indicated by reference numeral 10, comprising a horizontally disposed base 11, a vertically upstanding bracket 12,, a pair of arms 13, 14 which project sidewise from upstanding bracket 12 to overlie said horizontally disposed base 11, and a movable jaw 15. A pintle 16 is mounted in a bearing provided in said pair of arms 13, 14. law 15 is freely or loosely hinged to pintle 16 to be normally free to move automatically into vertical relation with horizontally disposed base 11, under the action of gravity.

A clamping area 18 is provided in the section of horizontally disposed base 11 underlying movable jaw 15.

Movable jaw 15 is provided with an operating leg 20 adapted to be actuated by a cam (not shown) which pivots jaw 15 into film release position, and a film engaging edge 5.

Horizontally disposed base 11 is connected to and forms part of an endless chain of which links 21, 22 form a part. Links 21, 22 are pivotally connected to horizontally disposed base 11 in a manner old in the art.

The present invention relates to a means for assisting the forces of gravity in more quickly pivoting the movable jaw 15 from film release position to film gripping position. Such means are illustrated in FIGURES 1 and 5 as being adjustable spring means. In FIGURES 2, 3 and 4 the means illustrated is a permanent magnet.

In FIGURES 1 and 5 bracket 12 is provided with a lug or boss 3% located on a line passing through the center of the length of the tenter clip 10. Lug 3% is provided am'ally with a screw thread 31. (See FIGURE 5.) A projection 32 is provided on movable jaw 15. A cap screw 33 provided with a spring seating recess 44 is rotatively mounted in screw thread 31. A lock nut 34 is rotatively mounted upon cap screw 33 and abuts surface 35 of lug 39 to lock cap screw 33 in adjusted position in lug 38. A coil spring 36 engages projection 32 and abuts surface 37 of movable jaw 15 on one end. The other end of coil spring 36 is located and seated in spring seating recess 44.

As the tenter chain travels around the sprockets (not shown) in a manner well known in the art, operating leg 2i) moves away from the cam (not shown) which held the movable jaw 15 in film release position. As soon as leg 20 disengages the cam (not shown) gravity, assisted by spring 36 causes leg 20 and movable jaw 15 to swing or pivot toward vertical or film gripping position. The present new and improved tenter clip is particularly adaptable to slimy plastic sheets, webs or film. It is necessary for the movable jaw to swing quickly into film gripping position and grip the film with a strong bite or the slimy slippery film will pull through the grip exerted by the film engaging edge 5 on the clamping area 18.

If the bite is too strong the extremely thin slippery film will tear and tentering will fail. It is therefore imperative to be able to adjust the spring tension exerted on the movable jaw 15 as the movable jaw swings or pivots into film gripping position.

In the past when the movable clamping jaw 15 swung down upon and engaged the cloth against the clamping area 18, the friction exerted by the cloth on the edge 5 of the movable jaw tended to pull the movable jaw 15 sneaess a forward so as to pinch the cloth between clamping area 18 and the film or cloth engaging edge 5.

The slimy slippery plastic film exerts no frictional contact on the film engaging edge of the movable jaw 15. Therefore, some form of assistance must be provided. Applicant has solved the problem with the auxiliary closing mechanism.

As the tenter clips travel around the sprockets (not shown), the nip exerted upon the film by the film engaging edge 5 of the movable jaw 15 and clamping area 18 must be exactly right. Too little nip results in the slipping away of the film from nipped or gripped position. Too much force tears the film. Yet the tenter clip is subject to strain as it travels. The strains are vibration, expansion and contraction due to atmospheric heat changes and the pull of the film. The gripping action must allow for some yielding in the firmness of grip. A coil spring provides for such a yielding action. Slippcry plastic film or very thin hard cloth or paper must be gripped more quickly and firmly than cotton cloth for example because the plastic film will not draw film engaging edge 5 into clamping position as cotton cloth will do.

In FIGURES 2, 3, 4 applicant illustrates the use of an adjustable magnetic field in place of an adjustable coil spring 36. A tenter clip, generally indicated by reference numeral A has substantially the same construction as tenter clip 18, and consists of a horizontally disposed base llA, a vertically upstanding bracket 12A, a pair of arms 13A, 14A which project sidewise from upstanding bracket 12A to overlie horizontally disposed base 11A, and a movable jaw 15A. A pintle 16A is mounted in said pair of arms 13A, 14A. Jaw 15A is loosely hinged to pintle 16A to be normally free to move automatically into vertical relation with horizontally disposed base llA, under the action of gravity. A clamping plate 15A may be secured to horizontally disposed base 11A in accordance with past custom in the art. Movable jaw 15A is provided with an operating leg 20A adapted to be actuated by a cam (not shown) which pivots movable jaw 15A into film release position. Movable jaw 15A is provided with a blade 5A in accordance with past custom in the art.

Bracket 12A is provided with a lug A. Lug 39A is provided axially with a screw thread 31A. A permanent magnet or a magnetically attractive metal plate 59 is provided with an externally threaded projection 51 adapted to be rotatively mounted in screw thread 31A. A nut 52 locks magnet or metal plate in selected adjusted position.

Operating leg 20A is provided with a tapped orifice 54. A second permanent magnet 56 provided with a counterbore 57 has an axially threaded area 58. A nonmagnetic collar 6!) may be placed against operating leg 20A. A screw 61 secures second permanent magnet 56 and collar 69 to operating leg ZtlA through rotatable engagement with threaded area 58 and tapped orifice 54.

As the tenter chain travels, operating leg 28A moves away from a cam (not shown). As soon as leg 20A disengages the cam (not shown) gravity and the force of the magnetic field cause leg 20A and movable jaw 15A to pivot toward a vertical position. Second permanent magnet 56 will move toward metal plate or permanent magnet 50. The influence of the magnetic field will cause second permanent magnet 56 to be attracted toward permanent magnet or metal plate 50 but they will never engage. If they engaged blade 5A would be locked or wedged in engagement with clamping plate 13A and the yielding influence of the magnetic field would be lost.

With reference to FIGURE 4, the poles of magnets 56, 56 are located to the rear of a vertical line through pintle 16A. It will be observed that as movable jaw 15A moves in clamping direction the second permanent magnet 56 approaches permanent magnet 50 so as to increase the effective magnetic field. The magnet field force increases as the magnets 56, 5-6 approach each other. They never meet. There must always be a small space or gap between them. It will be noted that permanent magnet 50 is adjustably secured in lug 36A through threaded projection 51 and nut 52.

In FIGURES 6, 7, 8 and 9 there is shown a modified form of tenter clip constructed in accordance with United States patent application Serial #823,886, filed June 30, 1959, for a Tenter Clip Gate, and in the instant inventors name.

These figures illustrated a tenter clip generally indicated by reference numeral 168, comprising a hori- Zontally disposed base 111-), a vertically upstanding bracket 123, a pair of arms 13B, 143 which project sidewise from upstanding bracket 1213 to overlie said horizontally disposed base 113, and a movable jaw 153. A pintle 16B is mounted in said pair of arms 13B, 1413. law 153 is loosely hinged to pintle 1613 to be normally free to move automatically into vertical relation with horizontally disposed base 118, under the action of gravity. A clamping area 183 is provided in the section of horizontally disposed base 113 underlying movable jaw 15B.

Movable jaw 15B is provided with an operating leg 25? adapted to be actuated by a cam (not shown) which pivots jaw 158 into film release position.

Tenter clip 18B forms part of an endless chain in the same manner as tenter clip 10 or tenter clip 10A and tenter clip 18C, presently to be described.

A gate 28 is pivotally mounted to movable jaw 153 by means of a shaft 38. Gate 28 comprises a counterweighted body member having as the oppositely aligned bearings 23B, 24B. Gate 2B as the body member is provided with a shoe face 278 terminating in an arcuate surface 63 the radius of which is on the vertical center of gravity of ate 2B. The vertical center of gravity is located to the rear of the vertical center of shaft 3B. Inspection of FIGURES 6, 7 and 9 will show that gate 23 engages clamping area 188 in a toggle action provided by means of pintle 16B and shaft 38.

Gate 213 is provided with a heel 298 which is of sufficient size and weight to form a counterbalance so that as gate pivots freely upon shaft 33 heel 298 will ang downwardly as shown in dot and dash lines in FIGURE 7 to initially engage clamping area 188 and pivot shoe face 2713 into engagement with clamping area 183.

Bracket 12B is provided with a lug or boss 39B located on a line passing through the center of the length of tenter clip lfiB. Lug 3GB is provided axially with a screw thread 313. A projection 32B is provided on movable jaw 153. A cap screw 333 provided with a spring seating recess 44B is rotatively mounted in screw threads 31B. A lock nut 34B is rotatively mounted upon the cap screw 33B and abuts surface 35B on lug 3013 to lock the cap screw is adjusted position in lug StlB. A coil spring 363 engages projection 32B and abuts surface 378 of movable jaw 1513 on one end. The other end of coil spring 368 is located and seated in spring seating recess 4 :3.

in operation coil spring 36B quickly pivots movable jaw 15B into film engaging position as operating leg 23B disengages the cam (not shown) which holds movable jaw 1513 in film release position. Gate 2B is then free under the action of gravity and in a toggle type of movement to engage clamping area 1813 or a film or web interposed between shoe face 278 and clamping area 18B.

It is absolutely imperative to be able to adjust the tension of coil spring 3613 so that the gravational movement of movable jaw 15B is in timed relation to the pivotal movement of gate 23 into film engaging position. if the timing is out of sequence shoe face 27B will engage clamping area 183 before the film is placed over clamping a-rea 18B. Tenter clip B will then fail to perform its function.

In FIGURE 10 there is illustrated a tenter clip generally indicated by reference numeral 100, comprising a horizontally disposed base 11C having a clamping area 18C, a vertically upstanding bracket 120, a pair of arm-s which project sidewise from upstanding bracket 12C to overlie clamping area 18C, and a movable jaw 15C. A pintle 16C is mounted in said pair of arms. Jaw 15C is loosely hinged to pintle 16C to be normally free to mom/e automatically into vertical relation with clamping area 18C, under the action of gravity. Movable jaw 15C is provided with an operating leg 20C adapted to be actuated by a cam (not shown) which pivots jaw 15C into film release position.

A gate 2C is pivotally mounted to movable jaw 15C by means of a shaft 3C. Gate 20 and gate 213 are identical in construction.

Bracket 120 is provided with a lug or boss C. Lug 30C is provided axially with a screw thread 310. A permanent magnet or a magnetic plate 500 is provided with an externally threaded projection 51C adapted to be rotatively mounted in screw thread 31C. A nut 52C locks magnet C in selected adjusted position.

Operating leg 20C is provided with a tapped orifice 54C. A second permanent magnet 56C provided with a counterbore 57' has an axially threaded area 58C. A non-magnetic collar 60C may be placed against operating leg 20C. A screw 61C secures second permanent magnet 56C and collar 60C to operating leg 20C through rotatable engagement with threaded area 58C and tapped orifice 540.

As previously described with reference to FIGURES 6, 7, 8 and 9, the magnets 50C, 56C of FIGURE 10 serve the same function as spring 3613.

Having shown and described preferred embodiments of the present invention by way of example, it should be realized that structural changes could be made and other examples given without departing from either the spirit or scope of this invention.

What I claim is:

1. A tenter clip comprising a horizontally disposed base having a clamping area, a vertically upstanding bracket having a lug provided axially with a screw thread, a pair of arm-s projecting sidewise from said upstanding bracket and overlying said clamping area, a movable jaw provided with an upstanding leg and a film engaging blade, a pintle mounted in said pair of arms, said movable jaw pivotally connected to said pintle to be normally free to move into vertical relation with said clamping area whereby said film engaging blade engages said clamping area under the action of gravity, an adjustable magnetic field interposed between said movable jaw and said lug comprising a permanent magnet and a metal plate, said metal plate having an axial threaded projection adapted to be rotatively mounted in said screw threads, means to secure said permanent magnet to said movable jaw, electrically insulated means interposed between said permanent magnet and said movable jaw whereby said magnetic field assists the forces of gravity in pivoting said movable jaw into vertical position.

2. A tenter clip comprising a horizontally disposed base having a clamping area, a vertically upstanding bracket having a lug provided axially with a screw thread, a pair of arms projecting sidewise from said upstanding bracket and overlying said clamping area, a movable jaw provided with an upstanding leg, a pintle mounted in said pair of arms, said movable jaw pivotally connected to said pintle to be normally free to move into vertical relation with said clamping area under the action of gravity, a gate comprising a counterweighted body having oppositely aligned bearings, said body provided with a shoe face terminating in an arcuate surface, said movable jaw having a shaft bearing, a shaft mounted in said shaft bearing, said gate loosely hinged through said oppositely aligned hearings to said shaft and movable jaw to be normally free under the influence of gravity to move into position with said arcuate surface engaging said horizontally disposed base, an adjustable magnetic field interposed between said movable jaw and said lug comprising a permanent magnet and a metal plate, said metal plate having an axial threaded projection adapted to be rotatively mounted in said screw threads, an electrically insulated collar, means to secure said permanent magnet and electrically insulated collar to said mowable jaw, whereby said magnetic field assists the forces of gravity in pivoting said movable jaw into vertical position and said shoe face into engagement with said clamping area in a film holding position.

References Cited in the file of this patent UNITED STATES PATENTS 1,119,824 Hayward Dec. 8, 1914 2,473,404 Young June 14, 1949 3,023,479 Nash Mar. 6, 196-2 3,046,599 Nicholas et al. July 31, 196-2 3,054,159 Mohring Sept. 18, 1962 FOREIGN PATENTS 1,265 Great Britain of 1882 3,099 Great Britain of 1889 1,069 Great Britain of 1914 483,688 Great Britain Apr. 25, 1938 862,319 Great Britain Mar. 8, 196 1 

1. A TENDER CLIP COMPRISING A HORIZONTALLY DISPOSED BASE HAVING A CLAMPING AREA, A VERTICALLY UPSTANDING BRACKET HAVING A LUG PROVIDED AXIALLY WITH A SCREW THREAD, A PAIR OF ARMS PROJECTING SIDEWISE FROM SAID UPSTANDING BRACKET AND OVERLYING SAID CLAMPING AREA, A MOVABLE JAW PROVIDED WITH AN UPSTANDING LEG AND A FILM ENGAGING BLADE, A PINTLE MOUNTED IN SAID PAIR OF ARMS, SAID MOVABLE JAW PIVOTALLY CONNECTED TO SAID PINTLE TO BE NORMALLY FREE TO MOVE INTO VERTICAL RELATION WITH SAID CLAMPING AREA WHEREBY SAID FILM ENGAGING BLADE ENGAGES SAID CLAMPING AREA UNDER THE ACTION OF GRAVITY, AN ADJUSTABLE MAGNETIC FIELD INTERPOSED BETWEEN SAID MOVABLE JAW AND SAID LUG COMPRISING A PERMANENT MAGNET AND A METAL PLATE, SAID METAL PLATE HAVING AN AXIAL THREADED PROJECTION ADAPTED TO BE ROTATIVELY MOUNTED IN SAID SCREW THREADS, MEANS TO SECURE SAID PERMANENT MAGNET TO SAID MOVABLE JAW, ELECTRICALLY INSULATED MEANS INTERPOSED BETWEEN SAID PERMANENT MAGNET AND SAID MOVABLE JAW WHEREBY SAID MAGNETIC FIELD ASSISTS THE FORCES OF GRAVITY IN PIVOTING SAID MOVABLE JAW INTO VERTICAL POSITION. 